In the past three years, to capitalize on the rebound in business travel, some airlines—Air France, Lufthansa, KLM, and Swiss among them—have launched all-business-class jets. Now, two start-up companies, Eos and Maxjet, are upping the ante with dedicated premium-class services.

Eos started daily flights this fall between New York's John F. Kennedy International and London's Stansted, with three Boeing 757's, which normally hold at least 200 seats, configured for 48 passengers. Seats recline flat and come with cashmere blankets. In November, Maxjet began flying the same route six days a week in Boeing 767's; these also typically hold 200 or more people, but Maxjet planes carry 102.

Industry analysts speculate that these new flights could drive down transatlantic business fares on the major airlines. At press time, Eos's round-trip fares were hovering at $6,500—roughly 25 percent less than British Airways' business-class fare from JFK to Heathrow. Maxjet's $1,358 fare is lower than both Virgin Atlantic's and British Airways' premium-economy seats. Its ticket prices are so low that they appear as "full-fare economy" seats in travel agents' distribution systems, which means executives whose companies ordinarily forbid them from flying business class can fly on Maxjet.